Bladder-Based Dispense System with Meniscus Control
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Solution Overview
Problem
In semiconductor fabrication, existing fluid delivery systems face challenges in maintaining high-purity and high-flow rate dispensing of chemicals onto substrates while minimizing defects caused by impurities, gas bubbles, and particle generation, which is exacerbated by the need for fine filters that reduce fluid flow rates and increase the risk of defects due to increased complexity in dispense line components.
Innovation Solution
A bladder-based fluid delivery system that uses an elongate bladder for indirect pressure/volume control, minimizing exposure to gas and atmosphere, reducing the number of dispense line components, and maintaining a linear fluid flow path to prevent cross-flows and particle formation, coupled with a meniscus sensor for precise control and digital suck-back functionality to maintain meniscus position and flow rate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If relatively fine filters are used to filter chemicals at point of use, then chemical purity is improved, but fluid flow rate decreases
Solution Approach 1:
The system pre-fills the elongate bladder with filtered chemistry before the dispensing operation. This preliminary filtration and storage action allows the use of fine filters without impacting real-time dispensing flow rate, as the filtering is completed in advance during the bladder filling phase.
Solution Approach 2:
The dispensing system is divided into separate functional phases: a pre-filling phase where chemistry is filtered and stored in the bladder, and a dispensing phase where pre-filtered chemistry is delivered. This segmentation allows filtration to occur without constraining the dispensing flow rate.
2Manufacturing precision
If more dispense line components are added to improve filtering, then chemical purity is improved, but device complexity increases
Solution Approach 1:
The system combines the filtration, storage, and dispensing functions into an integrated bladder-based system. The elongate bladder serves as both a storage reservoir and a dispensing mechanism, eliminating the need for separate filters, pumps, and control valves that would otherwise be required in traditional dispense lines.
Solution Approach 2:
Filtration is concentrated at the point where chemistry is loaded into the bladder, rather than distributing multiple filter components throughout the dispense line. This localized filtration approach achieves the required purity without dispersing complexity across multiple components.
3Productivity
If fluid is pushed through fine filters at high flow rate, then productivity is improved, but manufacturing precision deteriorates
Solution Approach 1:
Filtration is performed in advance during the bladder filling operation, allowing sufficient time for high-purity filtering without compromising dispensing speed. The pre-filtered chemistry is then stored in the bladder ready for rapid dispensing, decoupling the filtration time from the dispensing time.
4Ease of operation
If traditional dispense systems with multiple components are used, then ease of operation is maintained, but defectivity increases
Solution Approach 1:
The system extracts and removes traditional dispense line components (pumps, valves, connectors, tubing) that are sources of defects such as particle generation, gas bubbles, and contamination. The bladder-based system uses only the essential components needed for operation, eliminating defect sources while maintaining operational simplicity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system effectively reduces defectivity by maintaining high-purity and high-precision dispensing, minimizing gas dissolution and particle generation, and ensuring consistent flow rates, thereby improving the quality of deposited films by reducing the risk of defects such as bubbles, particles, and coagulation.
Implementation Method 1
The elongate bladder is configured to laterally expand and laterally contract within the chamber such that when the elongate bladder contains a volume of process fluid, the volume of process fluid within the elongate bladder is increasable and reducible
Implementation Method 2
A pressure-control system is provided that selectively decreases hydraulic fluid pressure on an exterior surface of the elongate bladder causing expansion of the elongate bladder. The meniscus position is also controlled by selectively increasing hydraulic fluid pressure on the exterior surface of the elongate bladder causing contraction of the elongate bladder
Implementation Method 3
A meniscus sensor is configured to continuously monitor a position of a meniscus of the process fluid within a nozzle region of the apparatus
Data Source
AI summary
Techniques herein include a bladder-based dispense system using an elongate bladder configured to selectively expand and contract to assist with dispense actions. This dispense system compensates for filter-lag, which often accompanies fluid filtering for microfabrication. This dispense system also provides a high-purity and high precision dispense unit. A meniscus sensor monitors a position of a meniscus of process fluid at a nozzle. The elongate bladder unit is used to maintain a position of the meniscus at a particular location by selectively expanding or contracting the bladder, thereby moving or holding a meniscus position. Expansion of the elongate bladder is also used for a suck-back action after completing a dispense action.